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Non-extensive effects on the QCD equation of state and fluctuations of conserved charges within Polyakov quark meson model

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JOURNAL OF PHYSICS G-NUCLEAR AND PARTICLE PHYSICS 2024年第6期51卷 065004-065004页

作者： Diab, Abdel Magied Modern Univ Technol & Informat MTI Fac Engn Cairo 11571 Egypt

The influence of non-extensive Tsallis statistics on the hadron phase structure has been investigated using the Polyakov-quark-meson (PQM) model. The analysis examines the non-extensive effects on the temperature dependence of PQM order parameters, thermodynamic quantities related to the quantum chromodynamics (QCD) equation of state, and fluctuations of conserved charges at varying chemical potentials. The results show that non-extensive effects have the most significant deviations near the crossover region. The pseudo-critical temperature T chi (mu B ) is not a universal constant and decreases with increasing non-extensive q parameter. The chiral phase diagram of the PQM model indicates a decrease in the behavior of the (T chi - mu B ) plane with increasing non-extensive q parameter. The PQM model exhibits good qualitative agreement with lattice QCD calculations. Moreover, these findings suggest the existence of a Tsallis limit, which serves as an alternative to the Stefan-Boltzmann limit for the massless ideal gas. The critical endpoint exhibits lower temperature but higher chemical potential with increasing non-extensive q parameter. Overall, this study highlights the importance of non-extensive Tsallis statistics in characterizing the quark-hadron phase structure of the PQM model and contributes to a deeper understanding of non-extensive effects in the quark-hadron phase transition.

关键词： chiral symmetries chiral transition chiral Lagrangian numerical approximation and analysis statistical models

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Day-ahead optimal scheduling of building energy microgrids based on time-varying virtual energy storage

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IET RENEWABLE POWER GENERATION 2023年第2期17卷 376-388页

作者： Mu, Yunfei Zhang, Yaqing Jia, Hongjie Yu, Xiaodan Zhang, Jiarui Jin, Xiaolong Deng, Youjun Tianjin Univ Minist Educ Key Lab Smart Grid Tianjin 300072 Peoples R China State Grid Tianjin Chengxi Elect Power Supply Bra Tianjin Peoples R China Tianjin Univ Key Lab Smart Energy & Informat Technol Tianjin M Tianjin Peoples R China

The thermal inertia of a building envelope endows a building with a heat storage capability, introducing scheduling flexibility to a building energy microgrid (BEM). The flexibility is usually modelled as virtual energy storage (VES) and used to optimize the operation of BEMs to reduce electricity costs. However, the VES capacity is impacted by and varies with variations in indoor/outdoor temperature. If only the building envelope's effect on heat transfer is considered, without proper quantification of scheduling flexibility provided by the building envelope, the scheduling scheme (especially VES charging/discharging schemes) will deviate from the actual VES operating conditions, which may affect the thermal comfort of individuals in buildings or bring high electricity costs. In this paper, a time-varying building VES model (TVES) with three time-varying parameters (virtual electric capacity (VEC), state of charge (SOC), and charge and discharge power) is proposed to quantify the electricity storage capability of the VES at different time periods for participating in operation of the BEM. Based on the TVES, a day-ahead optimal scheduling strategy is developed for the BEM to simultaneously reduce the electricity cost and guarantee the user's thermal comfort, where the proposed time-varying parameters of TVES are taken as constraints in the optimization. numerical studies verify the effectiveness of the proposed TVES and optimal scheduling strategy.

关键词： state of charge building energy microgrid heat storage capability virtual electric capacity Building structures Optimisation techniques Power system management, operation and economics power generation scheduling electricity storage capability heat transfer high electricity cost reduction buildings (structures) TVES numerical analysis cost reduction optimal scheduling strategy thermal energy storage BEM Storage in thermal energy numerical studies Heat and thermodynamic processes (mechanical engineering) building management systems power generation economics VES charging-discharging schemes numerical approximation and analysis building envelope endows VES capacity distributed power generation time-varying building VES model indoor-outdoor temperature Optimisation thermal comfort Buildings (energy utilisation) VEC indoor environment SOC numerical analysis day-ahead optimal scheduling strategy optimisation time-varying virtual energy storage Distributed power generation optimization process thermal inertia

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Optimal identification of model parameters for PEMFCs using neoteric metaheuristic methods

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IET RENEWABLE POWER GENERATION 2023年第3期17卷 659-680页

作者： Diab, Ahmed A. Zaki Abdelhamid, Ashraf M. Minia Univ Fac Engn Elect Engn Dept Al Minya Egypt Umm Al Qura Univ Coll Engn Commun & Elect Engn Dept Al Lith Branch Mecca Saudi Arabia

In this paper, the neoteric metaheuristic methods of artificial ecosystem-based optimization (AEO), Coot Bird-based optimization (COOT), Equilibrium optimizer (EQO), Runge-Kutta Method (RUN), Hunger games search (HGS), and Weighted Mean of Vectors (INFO) have been applied and evaluated to discover a preferable estimation for the Proton Exchange Membrane Fuel Cells (PEMFCs) model. The validation of the applied methods has been done for valuing the model parameters of BCS 500W-PEM, 500W-SR-12PEM, and 250W-stack. The objective function has been formulated as the sum of square errors (SSEs) between the measured and estimated data. MATLAB has been used for the verification of the optimization techniques. The results show that for BCS 500W-PEM: (1) the six algorithms can accurately solve the problem of the FC parameter assessment;(2) there are small distinguished between the six algorithms concerning their best value of the objective function;this distinction between the best and worst techniques is 2.4 x 10(-9);(3) the best algorithm is INFO with 0.011556306 while the worst algorithm is RUN with 0.011556308;(4) statistical results prove that the six algorithms have the tracking efficiencies of 99.99961329%, 99.97114568%, 99.83529736%, 100%, 99.89195368%, and 99.90200833% for AEO, COOT, EQO, INFO, HGS, and RUN, respectively based on 30 individual runs.

关键词： Equilibrium optimizer Optimisation techniques weighted mean of vectors Runge-Kutta Method BCS 500W-PEM metaheuristics measured estimated data RUN INFO Coot Bird-based optimization HGS 500W-SR-12PEM model parameters numerical approximation and analysis Runge-Kutta methods search problems optimization techniques Hunger games search EQO Fuel cells preferable estimation AEO Proton Exchange Membrane Fuel Cells model applied methods Differential equations (numerical analysis) worst algorithm FC parameter assessment artificial ecosystem-based optimization proton exchange membrane fuel cells neoteric metaheuristic methods objective function optimal identification

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On the solutions to Sylvester-conjugate periodic matrix equations via iteration

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IET CONTROL THEORY AND APPLICATIONS 2023年第3期17卷 307-317页

作者： Zhang, Lei Li, Pengxiang Han, Mengqi Zhang, Yanfeng Chang, Rui Zhang, Jinhua Henan Univ Sch Comp & Informat Engn Henan Prov Engn Res Ctr Spatial Informat Proc Henan Key Lab Big Data Anal & Proc Kaifeng 475004 Peoples R China Baoyuan Ind Investment Co Ltd Xinyang Peoples R China North China Univ Water Resources & Elect Power Sch Elect Engn Zhengzhou Peoples R China

The problem of solving a class of Sylvester-conjugate periodic matrix equations is investigated in this paper. Utilising conjugate gradient method, an iterative algorithm is provided, from which a matrix sequence can be generated to approximate the unknown matrix of the equation to be solved. Theoretical derivation proves that the proposed algorithm is convergent starting from any initial value, and simulation examples show the effectiveness of the proposed algorithm.

关键词： iterative algorithm matrix approximation conjugate gradient method Interpolation and function approximation (numerical analysis) Algebra, set theory, and graph theory conjugate gradient methods numerical approximation and analysis numerical analysis approximation theory matrix algebra Sylvester-conjugate periodic matrix equations matrix sequence convergence Linear algebra (numerical analysis)

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Joint Gramian inversion of gravity, magnetic and gravity gradient tensor data for the modelling of Mesoproterozoic iron oxide deposits, southeast Missouri, USA

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GEOPHYSICAL JOURNAL INTERNATIONAL 2023年第2期235卷 1064-1085页

作者： Vatankhah, Saeed Huang, Xingguo Renaut, Rosemary A. Mickus, Kevin Lin, Jun Jilin Univ Coll Instrumentat & Elect Engn Changchun 130026 Peoples R China Arizona State Univ Sch Math & Stat Sci Tempe AZ 85287 USA Missouri State Univ Dept Geog Geol & Planning Springfield MO 65897 USA

Within the iron metallogenic province of southeast Missouri, USA, there are several mines that contain not only economic iron resources, magnetite and/or hematite, but also contain rare earth elements, copper and gold. An area including three major deposits, Pea Ridge, Bourbon and Kratz Spring, was selected for detailed modelling for the upper crustal magnetic susceptibility and density structures. For the study area, ground gravity and high-resolution airborne magnetic and gravity gradiometry data sets are available. An efficient and novel joint inversion algorithm for the simultaneous inversion of these multiple data sets is presented. The Gramian coupling constraint is used to correlate the reconstructed density and magnetic susceptibility models. The implementation relies on the structures of the sensitivity matrices and an efficient minimization algorithm to achieve significant reductions in the memory requirements and computational costs. Consequently, it is feasible to use a laptop computer for the inversion of multiple data sets, each containing thousands of data points, for the recovery of models on the study area, each including approximately one million model parameters. This is the first time that these multiple data sets have been simultaneously inverted for this area. The L-1-norm stabilizer is used to provide compact and focused images of the ore deposits. For contrast, independent inversions of each data set are also discussed. In general, our results provide new insights about the concealed ore deposits in the Mesoproterozoic basement rocks of southeast Missouri. Both short- and long-wavelength anomalies exist in the recovered models;these provide a high-resolution image of the subsurface. The geometry and physical properties of the known deposits are determined very well. Additionally, some unknown concealed deposits are revealed;these could be economically valuable and should be considered in future geophysical and geological investigations.

关键词： Gravity anomalies and Earth structure North America Magnetic anomalies: modelling and interpretation Joint inversion numerical approximation and analysis

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Cherenkov Radiation:A Stochastic Differential Model Driven by Brownian Motions

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Computer Modeling in Engineering & Sciences 2023年第4期135卷 155-168页

作者： Qingqing Li Zhiwen Duan Dandan Yang School of Mathematics and Statistics Huazhong University of Science and TechnologyWuhan430074China Hubei Key Laboratory of Engineering Modeling and Scientific Computing Huazhong University of Science and TechnologyWuhan430074China

With the development of molecular imaging,Cherenkov optical imaging technology has been widely *** studies regard the partial boundary flux as a stochastic variable and reconstruct images based on the steadystate diffusion *** this paper,time-variable will be considered and the Cherenkov radiation emission process will be regarded as a stochastic *** on the original steady-state diffusion equation,we first propose a stochastic partial differential *** numerical solution to the stochastic partial differential model is carried out by using the finite element *** the time resolution is high enough,the numerical solution of the stochastic diffusion equation is better than the numerical solution of the steady-state diffusion equation,which may provide a new way to alleviate the problem of Cherenkov luminescent imaging *** addition,the process of generating Cerenkov and penetrating in vitro imaging of 18 F radionuclide inmuscle tissue are also first proposed by GEANT4Monte *** result of the GEANT4 simulation is compared with the numerical solution of the corresponding stochastic partial differential equations,which shows that the stochastic partial differential equation can simulate the corresponding process.

关键词： Cherenkov radiation stochastic partial differential equations numerical approximation and analysis GEANT4 Monte Carlo simulation

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Fixed-time stabilisation of boundary controlled linear parabolic distributed parameter systems with space-dependent reactivity

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IET CONTROL THEORY AND APPLICATIONS 2021年第5期15卷 652-667页

作者： Bao, Chunxia Cui, Baotong Lou, Xuyang Wu, Wei Zhuang, Bo Jiangnan Univ Sch IoT Engn Key Lab Adv Proc Control Light Ind Minist Educ Wuxi 214122 Jiangsu Peoples R China Binzhou Univ Sch Informat Engn Binzhou Peoples R China

The problems of state feedback and output feedback for fixed-time stabilisation of a linear parabolic distributed parameter system with space-dependent reactivity are considered by means of continuous backstepping approach and Lyapunov method. First, the invertible Volterra integral transformation with time dependent gain kernel is adopted to convert the original system into a fixed-time stable target system with time-dependent coefficient. The well-posedness of the resulting kernel equations is proved by the method of successive approximation. Then a state feedback controller is designed to guarantee fixed-time stabilisation of the closed-loop system. Moreover, a fixed-time observer is considered to estimate the state of the original system on the basis of the measurement signal at the boundary. Based on this observer, a observer-based output feedback controller is established to fixed-time stabilise the closed-loop system in a prescribed time by using separation principle. Finally, a numerical simulation is provided to verify the feasibility of the proposed theoretical results by using the modified Ablowitz-Kruskal-Ladik scheme.

关键词： numerical approximation and analysis Algebra Mathematical analysis Linear control systems Control system analysis and synthesis methods Stability in control theory Distributed parameter control systems Nonlinear control systems

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Investigation of numerical dispersion with time step of the FDTD methods: avoiding erroneous conclusions

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IET MICROWAVES ANTENNAS & PROPAGATION 2021年第7期15卷 691-703页

作者： Cheng, Yu Chen, Guangzhi Wang, Xiang-Hua Yang, Shunchuan Beihang Univ Sch Elect & Informat Engn Beijing Peoples R China Tianjin Univ Technol & Educ Sch Sci Tianjin Peoples R China Beihang Univ Res Inst Frontier Sci Beijing Peoples R China

To obtain high accuracy and efficiency in the simulations, an optimum time step should be taken in finite-difference time-domain (FDTD) methods. The authors investigated how time steps impact on numerical dispersion of two FDTD methods including the FDTD(2,2) method and the FDTD(2,4) method. Through rigorously analytical and numerical analysis, it is found that small time steps of the FDTD methods do not always have small numerical errors. Our findings reveal that these two FDTD methods present different behaviours with respect to time steps: (1) for the FDTD(2,2) method, smaller time steps limited by the Courant-Friedrichs-Lewy condition increase numerical dispersion and lead to larger simulation errors and (2) for the FDTD(2,4) method, as the time step increases, numerical dispersion errors first decrease and then increase. Our findings are also comprehensively validated from one- to three-dimensional cases through several numerical examples including wave propagation, resonant frequencies of cavities and a practical engineering problem.

关键词： convergence of numerical methods numerical dispersion finite difference time-domain analysis finite-difference time-domain methods time step Differential equations (numerical analysis) FDTD methods numerical analysis Courant-Friedrichs-Lewy condition Other numerical methods partial differential equations numerical approximation and analysis

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Conceptual method for the detailed analytical calculation of capacitance matrix elements in variable capacitance synchronous machines

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IET ELECTRIC POWER APPLICATIONS 2021年第5期15卷 513-527页

作者： Deylami, Fazel Pourmirzaei Darabi, Ahmad Shahrood Univ Technol Fac Elect Engn & Robot POB *** Shahrood Iran

This article describes a detailed analytical method for obtaining the capacitance matrix elements in variable capacitance synchronous machines (VCSMs). The analytical modelling approach is performed by introducing a decentralized sinusoidal distribution of the stator/rotor electrodes and involves obtaining the capacitance matrix elements based on the electro motive force distribution in the air gap and calculating the induced electric charge in the stator/rotor electrode surfaces. The proposed analytical formulas are valid for both radial-field and axial-field VCSM structures. The analytical model is evaluated and well verified through analysing a multi-stack axial-field VCSM using 3D finite element simulation. Furthermore, a prototype of the VCSM is manufactured and tested to validate the results obtained from the proposed analytical model and finite element method simulations. Based on the results, the proposed model and analytical formulas are able to accurately estimate the capacitance matrix elements of the VCSMs.

关键词： numerical analysis capacitance Finite element analysis analytical modelling approach finite element method simulations 3D finite element simulation capacitance matrix elements decentralized sinusoidal distribution variable capacitance synchronous machines numerical approximation and analysis radial-field VCSM structures detailed analytical method induced electric charge stators Protection apparatus axial-field VCSM structures finite element analysis rotors air gaps

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Solving 1D non-linear magneto quasi-static Maxwell's equations using neural networks

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IET SCIENCE MEASUREMENT & TECHNOLOGY 2021年第2期15卷 204-217页

作者： Baldan, Marco Baldan, Giacomo Nacke, Bernard Leibniz Univ Hannover Inst Electrotechnol Hannover Germany Politecn Milan Dept Aerosp Engn Milan Italy

Electromagnetics (EM) can be described, together with the constitutive laws, by four PDEs, called Maxwell's equations. "Quasi-static" approximations emerge from neglecting particular couplings of electric and magnetic field related quantities. In case of slowly time varying fields, if inductive and resistive effects have to be considered, whereas capacitive effects can be neglected, the magneto quasi-static (MQS) approximation applies. The solution of the MQS Maxwell's equations, traditionally obtained with finite differences and elements methods, is crucial in modelling EM devices. In this paper, the applicability of an unsupervised deep learning model is studied in order to solve MQS Maxwell's equations, in both frequency and time domain. In this framework, a straightforward way to model hysteretic and anhysteretic non-linearity is shown. The introduced technique is used for the field analysis in the place of the classical finite elements in two applications: on the one hand, the B-H curve inverse determination of AISI 4140, on the other, the simulation of an induction heating process. Finally, since many of the commercial FEM packages do not allow modelling hysteresis, it is shown how the present approach could be further adopted for the inverse magnetic properties identification of new magnetic flux concentrators for induction applications.

关键词： numerical approximation and analysis Electrostatics, magnetostatics Steady-state electromagnetic fields electromagnetic induction

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